The present invention relates to a circuit structure formed by insert-molding of electric and/or optical transmission medium in plastics. More particularly, it relates to a circuit structure wherein electronic devices can be wired and mounted at high density.
In the conventional electronic and electric devices, electric control signal transmission wiring and electric power transmission wiring are complicated. These are large obstacles to fulfilling the strong desires for reduction of assembling process steps, high level functions, and miniaturization. They have been problems that cannot be solved in the conventional technology.
On the other hand, there have been many disclosures about manufacturing methods of conductive circuit boards, including a two shot molding method, a photo-additive method and a subtraction method using plating, a printed circuit transfer method, a circuit printed film fusion mapping method, etc. However, these methods have a great number of processing steps, and disadvantages in heat resistance characteristics, and long term reliability, and therefore have not developed into practical use yet.
Japanese Patent Laid-Open 58-180095, discloses a structure and a method in which a printed-circuit board and cables are buried in plastics, and the structure is a housing in which the usual structure having usual electronic devices and parts implemented is fixed by plastics. However, this structure is insufficient in miniaturization and in reliability for such characteristics as heat resistance and thermal shock tesistance.